A type of a battery composed of Lithium, the lightest metal and the metal that has the highest electrochemical potential. Lithium, however, is an unstable metal, so these batteries are made from Lithium ions from chemicals. Because of its lightness and high energy density, these batteries are ideal for portable devices, such as notebook computers. In addition, Lithium-Ion batteries have no memory effect and do not use poisonous metals, such as lead, mercury or cadmium. The only disadvantage these batteries is that they are currently more expensive than NiCad and NiMH battery packs.